Changes between Initial Version and Version 1 of Docs/Prog/Manual/ApplicationLibraries/lib825

Timestamp:

11/30/09 14:29:44 (16 years ago)

Author:

Don Wilson

Comment:

--

Docs/Prog/Manual/ApplicationLibraries/lib825

@@ +1 @@
+= Standard 825 Library (lib825) =
+
+[[TOC(heading=Table of Contents, Docs/Prog/Manual/*)]]
+
+== Utility Functions ==
+Some simple routines may be used in the apps to convert between the hexadecimal strings and the various structures.
+
+{{{
+#!Lineno
+#!c
+unsigned char inline hex_char_val(char ch)
+{
+  if(ch >= '0' && ch <= '9')
+    return ch - '0';
+  else
+    return ch - 'A' + 10;
+}
+
+void inline convert_hex_to_binary(char *hex, unsigned char *out)
+{
+  int n = 0, i = 0;
+  while(hex[n] != 0)
+  {
+    out[i++] = (hex_char_val(hex[n]) * 16) + hex_char_val(hex[n + 1]);
+    if(hex[n + 1] == '\0')
+    {
+      printf("Invalid hex string\r\n");
+      break;
+    }
+    n += 2;
+  }
+}
+
+static char hexchar[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
+
+void binary_to_hex_str(unsigned char *in, unsigned char *out, int len)
+{
+  int n;
+  for(n = 0; n < len; n++)
+  {
+    out[n * 2] = hexchar[((0xF0 & in[n]) >> 4)];
+    out[n * 2 + 1] = hexchar[(0x0F & in[n])];
+  }
+  out[n * 2] = '\0';
+}
+}}}
+''These routines are packaged in [doxygen:hexutil_8cpp-source.html hexutil.cpp]''
+
+For example, an app may access time/date from the mainboard with the following:
+
+{{{
+#!c
+char* mnbd_dev "/dev/mnbd";
+int g_fileMnBd = 0;
+
+int OpenMnBd(void)
+{
+  /* O_NONBLOCK allows open even with no carrier detect */
+  g_fileMnBd = open(mnbd_dev, O_RDWR | O_NOCTTY | O_NONBLOCK);
+  if(g_fileMnBd == -1)
+  {
+    printf("Error opening %s\n", mnbd_dev);
+    return -1;
+  }
+  return 0;
+}
+
+void CloseMnBd(0)
+{
+  close(g_fileMnBd);
+  return;
+}
+
+int z;
+char readbuf![50];
+char rcvbuf![50];
+int rcvbufpos = 0;
+int nread;
+
+OpenMnBd();
+
+write(g_fileMnBd, "S\r", 2); // Request date/time from mainboard
+
+// In main loop of application:
+for(;;)
+{
+  nread = read(g_fileMnBd, &readbuf, sizeof(readbuf) );
+
+  if(nread > 0)
+  {
+    for(z = 0; z < nread; z++)
+    {
+      if(readbuf[z] == '\r')
+    {
+
+    rcvbuf[rcvbufpos] = '\0';
+
+    // When time/date is received from mainboard set the Linux clock
+    if(rcvbuf![0] == 'S')
+    {
+      struct mnbd_datetime_struct dt;
+      convert_hex_to_binary(rcvbuf + 2, (unsigned char *)&dt);
+      printf("Date/time from mainboard %d/%d/%d %d:%d:%d\r\n", dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second);
+  
+      // Set regular C tm struct to appropriate time values
+      struct tm time;
+      time.tm_year = dt.year - 1900;
+      time.tm_mon = dt.month - 1;
+      time.tm_mday = dt.day;
+      time.tm_hour = dt.hour;
+      time.tm_min = dt.minute;
+      time.tm_sec = dt.second;
+
+      time_t tt = mktime(&time);
+
+      stime(&tt);
+    }
+
+    rcvbufpos = 0;
+  }
+  else if(readbuf[z] >= 0x20 && readbuf[z] < 0x7F)
+  {
+    rcvbuf[rcvbufpos++] = readbuf[z];
+  }
+}
+}}}
+
+[[Top]]
+